Apparatus for maintaining the thickness of drawn glass



Jan. 2, J- U T APPARATUS FOR MAINTAINING THE'THICKNESS OF DRAWN GLASS Filed NOV. 9, 1929 d/A 5 de/aswzr if I fattommqs Patented Jan. 2, 1934 UNITED STATES PATENT OFFICE APPARATUS FOR MAINTAINING THE THICKNESS OF DRAWN GLASS Application November 9, 1929, Serial No. 406,012, and in France November 16, 1928 3 Claims.

This invention relates to an apparatus for substantially maintaining uniform the thickness of glass formed by a drawing operation from a source supplying glass at a variable rate, it consisting in automatically varying the speed of draw by and to compensate for accidental occasional variations in the thickness of the drawn glass. Such variations may be caused by change in viscosity and head of supply.

The invention here shown is applicable to the production of tubes or rods of uniform diameter and to the production of sheets of uniform thickness. Thus it is applicable to the drawing of tubes and rods by the process of United States patents to Danner No. 1,218,598 and to Fagan 1,273,345, and the production of sheets by the processes of United States Patents 745,487 and 836,439. These patents are cited merely by way of examples and it will be understood that the invention is not limited in its applicability to the process of the specified patents, but is generally applicable to processes in which the causes determining the thickness of the sheet include the viscosity of the glass, the rate the glass is fed from the source of supply, and the speed at which the article is formed.

Referring to the accompanying drawing in which corresponding parts are designated by similar marks of reference-- Figure 1 is a view partly diagrammatic of a structure embodying my invention and adapted to carry out the process herein claimed.

Figure 2 is a fragmentary view of outer ends of arms 4 and 5 of Figure 1, showing the same in use in sheet glass drawing.

The structure shown includes a suitable automatic thickness (diameter) calibrating device for the rod 10 or sheet 11, a variable speed drive for the draw mechanism and a pilot mechanism controlled by the extent of distension of the calibrating device for adjusting the variable drive mechanism. The specific embodiments of these parts may be varied from that shown, the mechanism illustrated being given as a specific eX- ample falling within my invention.

As represented, the calibrating device consists of two arms, 4 and 5, pivoted intermediate of their lengths on pivots 2 and 3, respectively, carried from a support 1 located adjacent to and at a proper point along the path of draw of the rod, the arms carrying at one end asbestos rubbing blocks 8 and 9, respectively, between which the rod passes, and being drawn together by a spring 6. The arms may be locked open by 5 a latch 7.

The arm 5 carries between its pivotal point and the rubbing block a valve body 13* in which moves a valve head 13 pressed towards its seat by a spring 14. The other arm carries an adjustable valve actuator in the form of a screw 12 adapted when drawn against the valve stem 13 to unseat the valve head. The described mounting of the arms causes the calipering mechanism to float with the swaying of the rod in its draw and by mounting the valve parts on the floating members this movement may take place without disturbing the position of the valve.

Flexible water induction and eduction pipes 17 and 18 enter the valve body on opposite sides of the valve seat, the induction pipe 1'7 being provided with a regulating cock 16. The pipe 18 discharging into a float chamber 36 having eduction pipes controlled by a cock 32 and also having an overflow pipe 33.

Contained within the float chamber is a float 31 mounted on the lower end of a vertically sliding stem 23 guided in the cover 20 of the chamber, the shaft having on its upper end a friction roller 28 forming the intermediate member of a variable speed device, the other members of which are the driving plate 26 and the driven plate 27 mounted respectively on the horizontal shafts 22 and 21, the shaft 21 being at a lower level than the shaft 22. The shaft 22 carries the driving pulley 25 by which motion is imparted thereto and the shaft 21 carries the drum 24 by which the glass drawing apparatus (which in the case of rod drawing by the structure shown in the Fagan patent are the gripping devices 5) is driven. The plates 26 and 27 are 99 pressed against the opposite sides of the friction roller 28 by springs 29 and 30 which bear on the ends of the shafts which carry the plates.

A pointer 34 mounted on a stem 23 and movable over a suitable scale serves to indicate the height of the flow.

In the operation of the device shown with the screw 12 set for the production of a predetermined diameter of rod 10, if the diameter of the rod is decreased for any reason as by a change of viscosity, the rubbing blocks are drawn together and the valve head 13 depressed, increasing the rate of flow of water through the pipe 18 to the float chamber. As the water level in the latter, and thus the vertical position of the float 31 therein, is determined by the relative rate of the flow and outflow therefrom (the latter being shifted by the cook 32) the float rises, moving the friction roller 28 closer to the center of the plate 26 and further from the center of the plate 27. Hence the drive of the drum 24 will be decreased as will be the speed of the draw.

It will be noted that the valve constitutes a pilot member between the calipering and the speed change mechanism.

In applying my invention to the structure shown in the Banner Patent 1,218,598 the variable speed drive would be coupled to the drawing means 23. In applying my invention to the structure of the Colburn Patent No. 836,439 the variable speed drive would be coupled to the means by which the glass is lifted from the bath i. e., the roller 45, and in applying it to the structure of the Frink, et al Patent 745,487, the variable speed drive would be coupled up to the carrier C.

Having thus described my invention what I claim as new and desire to secure by United States Letters Patent, is:

1. In a device of the character described for automatically maintaining substantially constant the thickness of drawn glass, the combination with a pair of pivoted arms having rubbing blocks in opposite sides of the glass, and forming a caliper, a valve structure carried by the caliper, means controlled by the degree of separation of the rubbing blocks determining the position of the valve, a variable speed drive, including a floating member, and means controlled by the valve determining the position of the floating member.

2. In a device of the character described for automatically maintaining substantially constant the thickness of drawn glass, the combination with a floating caliper comprising rubbing blocks on opposite sides of the drawn glass, a variable drive mechanism for determining the speed of draw of the glass and including a float chamber and a float therein, means for adjusting the outflow from the chamber and means for varying the inflow to the chamber, said last named means being mounted on and carried by the floating caliper.

3. In a device of the character described for automatically maintaining substantially constant the thickness of drawn glass, the combination with a floating caliper comprising rubbing blocks on opposite sides of the drawn glass, a variable drive mechanism for determining the speed of draw of the glass and including a float chamber and a float therein, means for adjusting the outflow from the chamber and means for varying the inflow to the chamber, the last named means comprising a valve body carried by one part of the caliper, and a valve stem whose position in the valve body is controlled by the position of the other member of the caliper.

JULES ARRAULT. 

